The present invention relates to a new and distinct cultivar of chrysanthemum plant, botanically known as Chrysanthemum×morifolium Ramat., commercially known as a garden mum, and hereinafter referred to by the cultivar denomination ‘Zanmukey’. ‘Zanmukey’ is a product of a breeding and selection program for outdoor pot mums (garden mums) which had the objective of creating new cultivars with a double type inflorescence, a natural season flowering date around September 28, blooming for a period of 5 weeks. ‘Zanmukey’ is a seedling resulting from a cross of the female parent 36.3379 (unpatented) with the male parent 10-010389 (unpatented). Plants of the new cultivar ‘Zanmukey’ differ from plants of the female parent in the following characteristics. (1) Inflorescence color—Blooms of the seedling are light green, while those of the female parent are white. (2). Inflorescence size—Blooms of the seedling are smaller than those of the female parent. Plants of the new cultivar ‘Zanmukey’ differ from plants of the male parent in the following characteristic. (1) Plant shape—the plant shape of the seedling is round, while that of the male parent is more erect.
The new and distinct cultivar was discovered and selected as a flowering plant by Henricus Cornelius Maria Jacobs on a cultivated field in Rijsenhout, The Netherlands in May 2011. The first act of asexual production of ‘Zanmukey’ was accomplished in July 2011 when vegetative cuttings from the initial selection were propagated further in a controlled environment in Rijsenhout, the Netherlands. In summer, about 6-8 days are needed to initiate roots in cuttings of the new cultivar, after another 5 days rooted plants are formed. The new cultivar has been found to retain its distinctive characteristics through successive propagations.